The invention concerns the field of flushing liquids for blood cells, in particular liquids for washing erythrocytes.
Flushing and storage liquids for blood cells, in particular for erythrocytes, are required in various processes. For example, in machine autotransfusion, that is to say obtaining and treating erythrocytes which are obtained intraoperatively, they are washed with a flushing liquid for subsequent retransfusion. In the machine treatment of blood components such as erythrocytes, leucocytes or thrombocytes, the cells are separated with a flushing liquid in so-called cell separators, so that they can be stored separately for a short period. The blood cells such as erythrocytes should be subjected to no changes or the minimum possible changes, by virtue of contact with such a liquid.
Nowadays the operation of flushing erythrocytes is usually implemented with physiological common salt solution. It is also known for so-called additive solutions such as for example mannitol, in the form of so-called SAG-mannitol or PAGGS-mannitol, to be added to erythrocyte concentrates to prolong the storage time (see Sibrowski, Anasthesiol. Intensivined. Notfallmed. Schmerzther. 1997, 32 (Suppl. 1), page 70). Gelatin-bearing infusion solutions are also known, but they have nothing to do with a use as flushing liquid for blood cells.
In regard to the washing of erythrocytes with NaCl-solution for autotransfusion it was found that the erythrocyte quality suffered from adverse effects due to the contact with the flushing liquid. Those erythrocyte quality losses are exhibited in particular due to impairment of the O.sub.2 -transport capability of the erythrocytes, which is characterised by the form and position of the so-called O.sub.2 -binding curve, by spontaneous haemolysis with the consequence of a rising haemoglobin and potassium concentration in the ambient liquid, by reduced 2,3-DPG- and ATP-content of the erythrocytes and disturbance in the acid-base housekeeping of the erythrocytes obtained. Quality losses of that kind are described in detail in the literature (see R. Karger, V. Kretschmer, Anaesthetist 1996, 45, pages 694-707; M. von Finck et al., Anaesthetist 1986, 35, pages 686-692). On the basis of present understanding in terms of the quality losses of erythrocytes their mechanical properties are in the forefront, with their consequences in regard to haemolysis and thus in regard to the loss of transfusable erythrocytes and the increase in extra-cellular free haemoglobin and potassium. The requirement accordingly is that erythrocyte preparations may only be transfused if haemolysis of the preparation is no greater than 0.8% (Council of Europe, Recommendations 1997).
It was in consideration of the quality impairments ascertained in respect of erythrocytes due to the contact with known flushing liquids that the object of the present invention arose, namely obtaining flushing liquids for blood cells, in particular erythrocytes, which do not involve any changes in the blood cells or at most slight changes such as to impair quality.